There are many applications where it is desirable to have access to numerous parts, each comprised of the same materials and having the same dimensions. There are also many applications where it is desirable to have access to numerous parts, each comprised of the same materials but having different sizes or shapes. In either case, one common approach is to have a supply of pre-cut parts; however, in some applications, it may be more efficient to have a continuous supply (e.g., a roll) of the material and cut individual parts from the roll as needed. This is particularly advantageous in applications where the size of the desired part is determined just prior to its application, and/or when there is a continuous distribution of desired sizes rather than a discrete number of part sizes.
In some applications, the precise dimensions of a cut part may be critical. For example, a lead-free wheel weight system is available from 3M Company (St. Paul, Minn.), which combines a lead-free wheel balancing material with an adhesive tape. The wheel weight system is available in rolls of various lengths, widths, and heights. Based on the particular density, width, and height of the material, parts having a desired weight can be produced by cutting a precise length from the roll stock. In some applications, e.g., wheel balancing, the length of the part (i.e., the lead-free wheel weight system) is determined shortly before the part is needed for assembly.
In many cut and dispense applications, a straight cut across the width and through height of the material is adequate. However, with thicker materials intended to be applied by hand the shape of the cut-edge may affect the ergonomics of the product and its intended use. For example, the repeated hand application of parts having sharp corners or edges may result in discomfort as a finger or thumb is pressed on or slid over the edge as the cut part is pressed into place.
The creation of a chamfered edge of a part to create a desired edge profile is known. As illustrated in FIG. 1, first chamfered corner 21 is the profiled portion of first cut edge 11 connecting top surface 30 and first cut side wall 31 of part 40. In some embodiments, second chamfered corner 22 forms part of second cut edge 12, and again connects to both top surface 30 and second cut side wall 32.
As used herein, a “chamfered corner” includes beveled corners and rounded corners. First chamfer 21 illustrates a beveled corner, i.e., a substantially planar corner intersecting the top surface and the cut side wall at angles other than 90 degrees. The term “substantially planar” is meant to encompass the normal variations typical in any manufacturing process including, e.g., some rounding at the intersection of the beveled corner and the top surface and at the intersection of the beveled corner and the side wall.
Referring to FIG. 1, the angle between the beveled corner and the cut side wall, A1, and the angle between the beveled corner and the top surface, A2, sum to 90 degrees. In some embodiments, angle A1 is at least 10 degrees, e.g., at least 20 degrees, or even at least 30 degrees. In some embodiments, angle A1 is no greater than 80 degrees, e.g., no greater than 70 degrees, or even no greater than 60 degrees. In some embodiments, angle A1 is between 30 and 60 degrees, inclusive, e.g., between 40 and 50 degrees, inclusive.
Second chamfered corner 22 illustrates a rounded corner. As used herein, a “rounded corner” consists essentially of a continuous, arcuate corner connecting the top surface to the cut side wall. The rounded corner may be convex or concave. The term “consists essentially of a continuous, arcuate corner” is meant to encompass the normal variations typical in any manufacturing process, particularly variations that can occur at the intersection of the chamfered edge and one or both of the top surface and the cut side edge.
Often, a chamfered corner is formed after a part is cut. Commonly, the chamfered is formed by removing (e.g., cutting or abrading) material near the intersection of the top surface and the cut edge until the desired profile is obtained. However, in rare applications (e.g., the creation of precision wheel weight segments) the removal of material would result in an undesirable decrease in the mass of the part. This problem could be overcome by molding parts with the desired profile; however, such an approach is not practical for on-demand application or applications requiring a continuous distribution of part sizes.
Therefore, it some applications, it may be desirable to provide a device capable of cutting a part to a desired length and creating a chamfered edge in the same step. It may also be desirable to create the chamfered edge without removing material.